For instance, Jupiter is the biggest planet in our solar system. Due to it's gravitational mass it can deflect meteorites and protect Earth from the Oort cloud. While these are positives, the negative effects are that Jupiter can draw comets in from the Kuiper belt which may have catastrophic consequences.

Any sources on the Jupiter - Oort cloud connection? Sounds interesting and I haven't heard of it before.
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SF.Oct 24 '13 at 10:33

Also, I'm not sure what you mean by 'Due to it's gravitational mass it keeps planets in orbit'. Could you reword or elaborate?
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astromaxOct 24 '13 at 13:03

@astromax - I have removed that line from my question as it may be inaccurate. I was under the assumption that each planet orbits the sun and the gravitational pull of both the Sun and Jupiter played a role in the orbital path for each planet.
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Darren DaviesOct 24 '13 at 13:12

This question would be better placed at Physics.SE
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Rory AlsopOct 24 '13 at 13:28

@SF. There is no connection between Jupiter and the Oort cloud. As Rory Alsop points out in his answer, because gravity falls off with the square of the distance, Jupiter has no effect on the Oort cloud.
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Donald.McLean♦Oct 24 '13 at 17:07

1 Answer
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The gravitational pull of all the planets and the sun, and the rest of the galaxy and the universe, all play a part, but gravitational effects fall off with distance.

For Earth's orbit, the Sun is far and away the single biggest influence. Jupiter perturbs our orbit slightly, but with it or without it we have a simple elliptical orbit round the sun. We can measure the perturbation in our orbit from all the planets, but the effects are minor.

When it comes to gravitational effects on small bodies passing one of the planets, however, the effects can be dramatic - an asteroid passing close to Jupiter will be moved far from its original path. The same would be true when passing close to Saturn or in fact any planet - just to a lesser degree.

So while you can't say that Jupiter protects Earth from anything, especially not the Oort Cloud, you also can't say that it draws objects in. Anything out in the Kuiper belt or Oort cloud will be orbiting the barycentre of the solar system (which is within the Sun) and will keep doing that unless knocked out by something like a collision with another object, or the pull of other Kuiper belt objects like Pluto, which can give a much greater tug.